In integrated circuits, voltage reference plays an important role. Voltage reference circuits are widely used in circuits that require a fixed voltage reference to be compared to for reliability and accuracy. For example, a voltage reference circuit in theory provides a voltage irrespective of power supply variations, temperature changes and the loading on the circuit. With the development of core device design, it may be desirable to have a voltage reference circuit that is able to operate at a relatively low bias condition and becomes less susceptible to process variation.